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Scanning electron microscopy and electron backscattered patterns, EBSP, have been employed to reveal both the grain structure and texture of 90% cold-rolled polycrystalline nickel after 1-hour anneals at a variety of temperatures. After annealing at either 400 degrees or 500 degrees C, small, cube-oriented, equi-axed grains were produced via primary recrystallization. At 600 degrees C, large [124]<211> oriented grains accounted for an increasing proportion of the microstructure, until at 1000 degrees C only large grains ( approximately 600 microm) and a sharp [124]<211> texture were present. Detailed EBSP analyses of the grain boundaries surrounding the large abnormally grown grains observed at 600 degrees C demonstrated that formation of the secondary recrystallization texture was due to migration of high-mobility, random high-angle boundaries around grains that had a size advantage, consistent with the Abbruzzese-Lücke model.

We have examined the effects of isothermal annealing, at a variety of temperatures, and directional annealing, under a range of conditions, on both primary recrystallization and secondary recrystallization in 90% cold-rolled 99.5% nickel of two different textures. The initial texture is shown to influence the rolling texture and, hence, the results of subsequent annealing. It was found that one alloy showed a cube texture after primary recrystallization, underwent abnormal grain growth upon annealing at high temperatures, and could be directionally (secondary) recrystallized to give large columnar grains. In contrast, the other alloy produce a weak cube texture after primary recrystallization, showed only normal grain growth upon annealing at higher temperatures, and could not be directionally annealed to produce columnar grains. The implications of these results are discussed for producing columnar grains.

Scanning electron microscopy (SEM) and electron back-scattered diffraction patterns (EBSP) have been employed to investigate the changes in the microstructure and texture of 90 % cold-rolled nickel when subjected to directional recrystallization. The effects of annealing temperature, hot zone velocity, and temperature gradient ahead of the hot zone on the microstructure were investigated.